Traffic light system



Sept. 13, 1966 P. LAFON TRAFFIC LIGHT SYSTEM 2 Sheets-Sheet 1 Filed Feb. 21, 1966 IN VE N 7'02 LMm Sept. 13, 1966 P. LAFON TRAFFIC LIGHT SYSTEM 2 Sheets-Sheet 2 Filed Feb. 21, 1966 5 R v. fi i United States Patent Ofiice 6 Claims. (Cl. 340-41 Conventional trafii c light systems comprise a set of coloured lights located at the edge of the carriageway on a post, or suspended above a crossroads, for example.

These systems possess a certain number of disadvantages, particularly when they are located at the edge of the carriageway since their signals are easily obturated by a vehicle that has come to a halt in front of them, while pedestrians crossing the road cannot see the colour of the lights since these are located in front of the crossmg.

Similarly, an arrangement of suspended traflic lights, while being easily visible, obliges the drivers of vehicles to look upwards, thus for a moment distracting their attention from the road on which they are driving, and this fact may make it necessary for the driver to manoeu-vre the vehicle sharply in order to avoid some unforeseen obstacle which has come into view while he was looking at the trafiic lights.

The invention has tor an object, a road traffic light indicator system which is easily visible to pedestrians and is always visible to drivers of vehicles who do not need to direct their attention away from the carriageway on which they are driving.

The invention consists in a road traflic light indicator system wherein a translucent strip is arranged in the carriageway at right angles thereto and is illuminated by means of coloured lights which are similar to traflic lights and which light up automatically by means which are conventional in the art of road trafiic light indications according to traffic requirements, the light strip being synchronised if desired with conventional road traffic light systems.

In a prototype embodiment, the strip is constituted by translucent tiles which are placed over a trench containing the traffic lights which illuminate the strip from below. The lights are in the form of light tubes carried by movable carriages, a lateral trench continuing or extending the light trench and enabling the carriages to be removed for maintenance work and also containing the trans-formers supplying current to the system and the indication control arrangement which may be manually or automatically operated.

Other additional characteristics of the invention will become clear from the following detailed description given with reference to the accompanying drawings. The description and drawings are, of course, merely given by way of nonlimiting example. In the drawings,

'FIGURE 1 is a view in vertical section of a system according to the invention,

FIGURE 2 is a plan view of the system shown in FIG- URE 1,

FIGURE 3 is a section along the lines III-III of FIG- URE 1, shown to a larger scale, and

FIGURE 4 is a view similar to that of FIGURE 1 but on a larger scale to illustrate a coupling for the two carriages.

Referring now to the drawings, a road traflic light system is shown that comprises a translucent strip I mounted in the surface of the carriageway and at right angles thereto and composed of tiles 2 made of rough sand-cast glass.

3,273,115 Patented Sept. 13, 1966 These tiles 2 cover a trench formed by a concrete casing 3 which has at its upper end a shoulder 4 on which the tiles rest by means of a sealing joint 5 inserted between the shoulder and the tiles, so that the upper surface of the tiles is substantially the same level as the carriageway.

Within the casing 3 are located light tubes 6. These tubes are grouped in threes, the three tube-s being of different colours, viz. red, amber and green, as laid down in most highway regulations, and mounted parallel on a carriage 7 comprising a frame 8 mounted on two wheels 9, the tubes being carried on the frame by means of supports 10, each of which has, in its upper portion, three semicylindrical seatings 10a in which are mounted the tubes 6.

The casing 3 may, for instance, be of small dimensions such as mm. in width and 250 mm. in depth, this depth being less towards the edges of the carriageway when the latter is slightly curved; the base of the casing is also slightly domed in order to allow water which has penetrated or condensed in the casing to flow oil and be removed.

A number of carriages is arranged in series in the easing and these carriages are coupled together by mechanical means such as a flexible coupling 11 and by electrical means such as conductors 12 which connect in series the tubes of the same colour, the conductors 12 having terminals 12a which are easily releasable and are screwed on to base 6a of the tubes, through which they receive current.

Moreover, in order to facilitate maintenance, a trench '13 extends the casing 3 so that the carriages 7 may be successively removed.

This trench 1-3 is hollowed out of the pavement T or the side of the carriageway and comprises an enlarged portion 14 in which are located three transformers 15 which supply current to a series of like colour tubes and which are each connected to a high voltage discharge tube on the first carriage and to a tube on the second carriage by means of cables 16 which pass through a pipe 17 embedded in the concrete casing 3.

The trench 13 also comprises a ventilating grid 18 and an outlet 19 for the water produced by condensation within the casing 3 and the trench 13.

The tubes 6 have been developed to ensure that the colours obtained are clearly distinguishable. The red colour, for example, is obtained using a conventional neon strip and a wall of the tube as a filter to prevent penetration of the amber coloured rays of the neon spectrum, while in order to obtain the amber colour, the yellow wall of the tube absorbs the red part of the emitted spectrum which is selected to be centred on orange. Finally, green is obtained by the emission of a relative amount of zinc oxide, for example, which produce-s a spectrum which is clearly distinguishable from the other two.

These tubes, which are supplied with current in a conventional manner through the transformers 15 which are provided with a magnetic current limiting device, are controlled at their primary side by manually or automatically operated devices provided with relay means similar to that conventionally employed in known road trafiic signal systems using lights.

The control means may be located in the enlarged portion of the trench 14 or adjacent the control boxes for existing traflic lights.

The invention is by no means limited to the one embodiment herein described and shown but extends to all modifications within the scope of the appended claims. In particular, it is possible to illuminate the translucent strip from the side instead of from below.

I claim:

1. A road tratfic light system comprising a translucent strip, means for mounting said strip in a carriageway at right angles thereto, a plurality of coloured lights, means for mounting said lights beneath said strip, and automatically operable control means for energising said lights cyclically in dependance upon trafiic requirements.

2. A system according to claim 1, comprising in addition, conventional side track or overhead mounted traffic lights and means for synchronising said lights beneath said strip with said conventional traflic' lights.

3. A system according to claim 1, wherein said strip is composed of translucent tiles and wherein said coloured indicator lights are mounted in a trench, said strip being mounted from below and said trench to be illuminated by said lights.

4. A system according to claim 1, wherein said lights are in the form of light tubes carried by movable carriages which are provided With means for coupling them electrically and mechanically.

5. A system according to claim 3, wherein a second trench laterally extends said light trench to allow mounting means for said lights, in the form of carriages, to be removed for maintenance work, said second trench also containing current supply transformers for the system and indicator control means.

6. A system according to claim 3, wherein a concrete casing is located in said trench and is provided with a shoulder and a joint on which said tiles rest.

No references cited.

THOMAS B. HABECKER, Acting Primary Examiner. 

1. A ROAD TRAFFIC LIGHT SYSTEM COMPRISING A TRANSLUCENT STRIP, MEANS FOR MOUNTING SAID STRIP IN A CARRIAGEWAY AT RIGHT ANGLES THERETO, A PLURALITY OF COLOURED LIGHTS, MEANS FOR MOUNTING SAID LIGHTS BENEATH SAID STRIP, AND AUTOMATICALLY OPERABLE CONTROL MEANS FOR ENERGISING SAID LIGHTS CYCLICALLY IN DEPENDANCE UPON TRAFFIC REQUIREMENTS. 